"Victoria you played unbelievable," Williams said. "What a great match and a great person. It's an honor to play against you." she told the crowd after winning her second grand slam title this year, having also lifted the French Open in June.

Azarenka, beaten by Williams in the final in New York for the second straight year, admitted a second defeat was hard to take.

"It's a tough loss but being in the final against the best player, who deserves the win, it's incredible," the Australian Open champion said.

"I gave it everything I had. I fought hard but well deserved. Congratulations Serena."

Bumper check

Williams picked up a check for $3.6 million, including a $1 million bonus for winning events in the build-up to the final slam of the season -- though she lost to Azarenka in the Cincinnati final last month, just one of four defeats for her in 2013.

She is the first woman to successfully defend the title since Kim Clijsters in 2010, and was runner-up in the 2011 final in New York.

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Williams had lost only 16 games in six matches as she cruised to the final, but Azarenka was made of sterner stuff and after dropping her service in the very first game, immediately broke back to set the pattern of the final.